Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model
A method is described to estimate the thickness of glacier ice using information derived from the measured ice extent, surface topography, surface mass balance, and rate of thinning or thickening of the ice column. Shear stress beneath an ice column is assumed to be simply related to ice thickness a...
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American Meteorological Society
2013
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Online Access: | https://www.zora.uzh.ch/id/eprint/86859/ https://www.zora.uzh.ch/id/eprint/86859/1/2013_BolchT_ClarkeAl13_JClim_GlacBedWCan_.pdf https://doi.org/10.5167/uzh-86859 https://doi.org/10.1175/JCLI-D-12-00513.1 |
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ftunivzuerich:oai:www.zora.uzh.ch:86859 2024-06-23T07:53:05+00:00 Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model Clarke, Garry K C Anslow, Faron S Jarosch, Alexander H Radić, Valentina Menounos, Brian Bolch, Tobias Berthier, Etienne 2013 application/pdf https://www.zora.uzh.ch/id/eprint/86859/ https://www.zora.uzh.ch/id/eprint/86859/1/2013_BolchT_ClarkeAl13_JClim_GlacBedWCan_.pdf https://doi.org/10.5167/uzh-86859 https://doi.org/10.1175/JCLI-D-12-00513.1 eng eng American Meteorological Society https://www.zora.uzh.ch/id/eprint/86859/1/2013_BolchT_ClarkeAl13_JClim_GlacBedWCan_.pdf doi:10.5167/uzh-86859 doi:10.1175/JCLI-D-12-00513.1 urn:issn:0894-8755 info:eu-repo/semantics/openAccess Clarke, Garry K C; Anslow, Faron S; Jarosch, Alexander H; Radić, Valentina; Menounos, Brian; Bolch, Tobias; Berthier, Etienne (2013). Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model. Journal of Climate, 26(12):4282-4303. Institute of Geography 910 Geography & travel Journal Article PeerReviewed info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2013 ftunivzuerich https://doi.org/10.5167/uzh-8685910.1175/JCLI-D-12-00513.1 2024-06-12T00:30:48Z A method is described to estimate the thickness of glacier ice using information derived from the measured ice extent, surface topography, surface mass balance, and rate of thinning or thickening of the ice column. Shear stress beneath an ice column is assumed to be simply related to ice thickness and surface slope, as for an inclined slab, but this calculation is cast as a linear optimization problem so that a smoothness regularization can be applied. Assignment of bed stress is based on the flow law for ice and a mass balance calculation but must be preceded by delineation of the ice flow drainage basin. Validation of the method is accomplished by comparing thickness estimates to the known thickness generated by a numerical ice dynamics model. Once validated, the method is used to estimate the subglacial topography for all glaciers in western Canada that lie south of 608N. Adding the present ice volume of each glacier gives the estimated total volume as 2320 km3, equivalent to 5.8 mm of sea level rise. Taking the glaciated area as 26 590 km2 gives the average glacier thickness as 87.2 m. A detailed error analysis indicates that systematic errors are likely to increase the esti- mated sea level rise and when random errors are included the combined result is 6.3 6 0.6 mm or, expressed as ice volume, 2530 6 220 km3. Article in Journal/Newspaper glacier* University of Zurich (UZH): ZORA (Zurich Open Repository and Archive Canada |
institution |
Open Polar |
collection |
University of Zurich (UZH): ZORA (Zurich Open Repository and Archive |
op_collection_id |
ftunivzuerich |
language |
English |
topic |
Institute of Geography 910 Geography & travel |
spellingShingle |
Institute of Geography 910 Geography & travel Clarke, Garry K C Anslow, Faron S Jarosch, Alexander H Radić, Valentina Menounos, Brian Bolch, Tobias Berthier, Etienne Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
topic_facet |
Institute of Geography 910 Geography & travel |
description |
A method is described to estimate the thickness of glacier ice using information derived from the measured ice extent, surface topography, surface mass balance, and rate of thinning or thickening of the ice column. Shear stress beneath an ice column is assumed to be simply related to ice thickness and surface slope, as for an inclined slab, but this calculation is cast as a linear optimization problem so that a smoothness regularization can be applied. Assignment of bed stress is based on the flow law for ice and a mass balance calculation but must be preceded by delineation of the ice flow drainage basin. Validation of the method is accomplished by comparing thickness estimates to the known thickness generated by a numerical ice dynamics model. Once validated, the method is used to estimate the subglacial topography for all glaciers in western Canada that lie south of 608N. Adding the present ice volume of each glacier gives the estimated total volume as 2320 km3, equivalent to 5.8 mm of sea level rise. Taking the glaciated area as 26 590 km2 gives the average glacier thickness as 87.2 m. A detailed error analysis indicates that systematic errors are likely to increase the esti- mated sea level rise and when random errors are included the combined result is 6.3 6 0.6 mm or, expressed as ice volume, 2530 6 220 km3. |
format |
Article in Journal/Newspaper |
author |
Clarke, Garry K C Anslow, Faron S Jarosch, Alexander H Radić, Valentina Menounos, Brian Bolch, Tobias Berthier, Etienne |
author_facet |
Clarke, Garry K C Anslow, Faron S Jarosch, Alexander H Radić, Valentina Menounos, Brian Bolch, Tobias Berthier, Etienne |
author_sort |
Clarke, Garry K C |
title |
Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
title_short |
Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
title_full |
Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
title_fullStr |
Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
title_full_unstemmed |
Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
title_sort |
ice volume and subglacial topography for western canadian glaciers from mass balance fields, thinning rates, and a bed stress model |
publisher |
American Meteorological Society |
publishDate |
2013 |
url |
https://www.zora.uzh.ch/id/eprint/86859/ https://www.zora.uzh.ch/id/eprint/86859/1/2013_BolchT_ClarkeAl13_JClim_GlacBedWCan_.pdf https://doi.org/10.5167/uzh-86859 https://doi.org/10.1175/JCLI-D-12-00513.1 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
glacier* |
genre_facet |
glacier* |
op_source |
Clarke, Garry K C; Anslow, Faron S; Jarosch, Alexander H; Radić, Valentina; Menounos, Brian; Bolch, Tobias; Berthier, Etienne (2013). Ice volume and subglacial topography for western Canadian glaciers from mass balance fields, thinning rates, and a bed stress model. Journal of Climate, 26(12):4282-4303. |
op_relation |
https://www.zora.uzh.ch/id/eprint/86859/1/2013_BolchT_ClarkeAl13_JClim_GlacBedWCan_.pdf doi:10.5167/uzh-86859 doi:10.1175/JCLI-D-12-00513.1 urn:issn:0894-8755 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5167/uzh-8685910.1175/JCLI-D-12-00513.1 |
_version_ |
1802644577942765568 |